Hi all, I've modified the pidgin's notification plugin to make it notify via file. the code is at: http://glua.ua.pt/~htavares/sane-notify.tar
You need to edit sanenotify.c to define the notification file. You may need to apt-get build-dep pidgin or apt-get install pidgin-dev. After compile and install procedures, you will find 'Sane Notification plugin' in pidgin's plugin list. The notification file will contain the number of conversations having new messages. This is just a little hack made in a couple of minutes, it's not well tested, i'm going to work on this tomorrow or so, btw i'm requesting for comments, ideas, anything. -htr
